The cam used in both the 306 and 347 was from Comp Cams. As both test motors were built using late-model 5.0 blocks, we utilized a hydraulic-roller profile. The Xtreme Energy series was chosen for maximum power and driveability. The dual-pattern XE282HR offered a 0.565/0.574-lift split and 232/240-duration split. Lobe center checked in at 112 degrees. The cam was run with matching 1.6 ratio roller rockers to arrive at the designated lift values. The pistons in both motors were notched in anticipation of the near-0.600 valve-lift numbers.